Re: Still APC detection anomaly...

Dear Flowers,

I got many responses from the community for my question ( http:// 
www.cyto.purdue.edu/hmarchiv/current/2045.htm ). Thanks.

Up to now I tried the following tests:

1. Detector: I replaced the APC detector with an other one (same  
type) but I got the same strange results altough the replacement  
detector works fine in the FL5 channel (PE-Alexa700) without negative  
events at low gains. By the way all the other detectors collecting  
light from the blue laser excited fluorochromes work fine. I mean I  
always get nice peaks without negative events even at low gains, only  
the the position of the peaks shifts towards the lower values. These  
results tell me that the detector should be OK.

2. Filters: I replaced the bandpass emission filter in the front of  
the detector without success.

3. Time delay adjustment: I tried to fine tune the laser aligment but  
all the same.

4. Using higher gains in the APC channel: altough I used higher gains  
where no negative events were seen using calibration beads I got high  
proportion of CD7 APC negative T-cells again. I think the dim signal  
of the T cells produce the same effect like the low gain.

So I'm still waiting for the solution :-(

Bests,

Pal Jakso

University of Pecs
Faculty of Medicine
Dept. of Pathology
12. Szigeti str.
H-7643 Pecs, HUNGARY